Underreamer for drilling oil-wells.



W. P. REEVES.

AMER FOR DRILLING v WALTER I. REEVES 0F MARICOPA, CALIFOR1\TI&.

UNDERREAMER FOR DRILLING 0IL-WELL$.

nesassa To all whom it may concern:

Be it known that I, WALTER P. REEVES, a citizen of the United States, residin at Maricopa, in the county of Kern and tat-e of California, have invented certain new and useful Improvements in Underreamers for Drilling Oil-Wells, of which the following is a specification, reference being had tothe accompanying drawings.

This invention relates to reamers used 1n underreaming the wall of a drill hole ahead of the well casing.

lhe general object of the invention is to provide a reamer of this character which is so formed as to eliminate the fi'ictional engagement of the reamer with the well casmg or with the wall of the well.

A further object is to provide the reamer I with a plurality of water channels extending longitudinally of the reamer, which enables the reamer to drop free under ordmary circumstances.

A further object is to provide a reamenof this character having cutting blades with means for preventing the cutting blades from dropping out of the reamer in case of by permitting the blades to be fished out with the ordinary horn socket.

A further object is to so construct the reamer that cutting blades may be used having arcuate cutting edges to an extent nearly one-half of the circumference of the reamers.

Other objects will appear in the course of the following description. I

My invention is illustrated in the accom panying drawings, wherem:-

Figure 1 is a side elevation of my reamer;

Fig. 2 is a vertical longitudinal section thereof on the line 2-2 of Fig. 4;

Fig. 3 is a longitudinal section thereof on the line 3-3 of Fig. 4;

Fig. 4 is a bottom plan view; Fig.1?) is a section on the line 5'-5 of Fig. 2; an

Fig. 6 is a section on the line 6-6 of Fig. 2.

Referring to these drawings, it will be seen that the body of the reamer consists of the, shank 10, which at its upper end is reduced and screw-threaded for engagement Specification of Letters Patent. Application filed April 29, 1918. Serial N0. 231,465.

Patented Nov. 5, 1913.

" with the shackle, which connects the reamer to the drill cable, the shank being reduced in cross sectional area at 11 and preferably made rectangular at thispoint. This shank 10 increases in diameter from the upper end toward the lower end, in other words, is upwardly tapering, and at its lower end the shank is reduced in diameter to form a central portion 12 and the annular shoulder 13. This reduced portion of the shank is formed with a longitudinally extending, transverse slot 14, the lower wall of this slot being defined by the transverse web 15. lit will be noted that the central portion 12 is downwardly tapered and that this web 15 is downwardlly beveled. Each of the cutting bits or blades 16 at its upper end is formed to fit firmly against the shoulder 13 and against the central portion 12. The inner face of each blade 16 is downwardly and centrally inclined as at 17 for the greater portion of its length, and this inner face is downwardly and outwardly inclined as at 18, the lower extremity of each bit being cut away as at 19 to provide a cutting edge 20 for each bit.

The bits 16 are held inplace in my reamer by means of a transverse key 21 rectangular in cross section, which passes through the upper ends of .both blades and which normally bears against the under face of the central portion 12. This key 21 is formed with a downwardly projecting stud 22 at its middle, and engaging with this stud is a vertically extending pin 23 which has a socket at its upper end for engagement with the stud and is also formed with a slightly enlarged head sweated, brazed, or otherwise attached to the pin 23 and which bears against the key 21, this pin extending downward through a passage 24 in the web 15 and being slidable in this passage. Disposed be tween the head of the pin 23 and the web 15 isa coiled expansion spring 25, which urges the pin 23 and the key 21 upward. The lower end of the pin 23 is provided with a perforation 26 whereby the pin may be engaged with a tool and drawn backward against the force of the spring 25.

It will be seen that under ordinary circumstances, when the tool is in use, the spring 25 will urge the bits 16 upward so that the beveled faces of the web 15 acting against the beveled inside faces of the bits will cause the lower ends of the bits to spread so that the diameter of the reamer than the diameter of the body of the reamer. Now if it be desired to cause the lower ends of the bits to move inward, the pin 23 is engaged by any suitable tool, and the pin or king bolt, as it may be termed is drawn downward, drawing downward on the bits, so that the bits may be forced toward each other to permit the bits to enter the well casing. As soon, however, as the pin or king bolt is released, the spring will cause the bits to be drawn upward and the wedging action. of the inclined faces of these bits against the inclined faces of the web 15 will cause the bits to expand.

Preferably, the web 15 and the adjacent portion of the body 10 are formed with the longitudinally extending water channels or grooves 27. These water channels or grooves permit the tool to drop perfectly free under ordinary circumstances, in other words. permit the reamer to pass through a body of water which would otherwise obstruct its passage.

it will be seen that the key 21 holds the bits in place to the body of the reamer by the engagement of this key with the king bolt 23 and by the action of the spring 25. In case the spring should break, the king bolt with the key and bits will drop downward, but the web 15 would prevent the entire detachment of the key and bit from the body of the reamer. The reamer can then be withdrawn and a new spring readily inserted.

It will be noted that the reamer is tapered upward from the lower ends of the bits to the top of the body, this form bein of importance, inasmuch as it entirely eliminates the frictional engagement of the reamer with the well casing or with the wall of the hole in which the reamer is operating. It is also to be noted that the bits are relatively long in proportion to the largest diameter of the reamer, so that in case the bits become detached from the reamer and drop into the hole, they cannot turn over or get crosswise of the hole. This construction permits these bits to be readily fished out with the ordinary horn sockets. It will be noted also that, the inner faces of the bits are inclined uniformly upward and outward in exact conformityto the inclination of the confronting faces of the web 15 and the confronting faces of the central portion 12, this inclination being such that when the bits are pulled down, by pulling down on the king bolt, the bits may be forced inward to an extent necessary for the bits to enter a casing having a diameter properly proportionate to the size of the reamer used.

It will likewise be seen that the bits bear firmly against the body of the reamer and against the shoulder 13 so that the bits are fully supported against the blows struck by the reamer and that the cutting edge of each bit is nearly semi-circular in cross section at its lower end, so as to exert a cutting action over a very large part of the circumference of the reamer. Throughout the construction of this reamer, all set screws, lock nuts and like parts are eliminated so as to prevent the parts of the reamer becoming accidentally detached.

Having described my invent-ion what I claim is:

A reamer of the character described comprising an upwardly tapered body, the lower end of the body being formed with a reduced and downwardly tapered ortion said reduced portion of the body being formed with a longitudinally extending transverse slot, oppositely disposed cutting bits bearing against opposite faces of the reduced portion, the inner faces of the bits being inclined upward and outward and bearing against the inclined faces of the reduced portion, a key detachably disposed through the upper ends of the bits and through said slot, a vertical pin slidingly mounted in the lower wall of the slot and having a recess in its upper end, the key having a lug fitting in said recess, and a coiled spring surrounding the pin and bearing against the upper end thereof and at its lower end bearing against the lower wall of the slot, thelower extremity of the pin being formed with a perforation whereby it may be retracted.

In testimony whereof I hereunto afiix my signature in the presence of two witnesses.

WALTER P. REEVES.

Witnesses:

CHARLES W. BnUDo, JEAN DEL BONDIO. 

